Pump unit for conveying high temperature media

ABSTRACT

A pump unit for conveying high temperature media having an air cooled drive motor and a centrifugal pump wherein said drive motor is mounted so as to cause cooling air to pass over the shaft sealing housing and reduce the temperature in the area of the shaft packing.

United States Patent 1191 Hagemann et a1.

PUMP UNIT FOR CONVEYING HIGH TEMPERATURE MEDIA Inventors: Walter Hagemann, Itzehoe-Nordoe;

Erwin Zimmermann, Heiliggenstedten-Julianka, both of Germany Siemens & Hinsch mlJH,

ltzehoe/Holstein, Germany Filed: Dec. 14, 1970 Appl. No.1 97,910

Assignee:

Foreign Application Priority Data Dec. 23, 1969 Germany P 19 64 474.7

US. Cl. 417/423 R, 415/112 Int. Cl. F04d 7/06, F04d 13/06 Field of Search 310/58, 57, 59;

References Cited UNITED STATES PATENTS Priest et al 415/112' 11] 3,738,781 June 12, 1973 2,864,314 12/1958 Culleton 415/112 3,554,661 l/197l Oglesby et al.. 415/1 12 2,601,146 6/1952 Ivanoff 417/424 2,799,522 7/1957 King et a1. 277/22 FOREIGN PATENTS OR APPLICATIONS 114,725 10/1929 Austria 415/111 208,660 11/1968 Sweden.... 1,177,354 12/1958 France Primary Examiner-Henry F. Raduazo Attorney-John Lezdey [57] ABSTRACT A pump unit for conveying high temperature media having an air cooled drive motor and a centrifugal pump wherein said drive motor is mounted so as to cause cooling air to pass over the shaft sealing housing and reduce the temperature in the area of the shaft packing.

6 Claims, 3 Drawing Figures PAlEmEn JUN 1 2191s SHEEY 1 0 2 l llllf sm i I $1 WALTER HAGEMA/VN T ER d/N z/ N PUMP UNIT FOR CONVEYING HIGH TEMPERATURE MEDIA BACKGROUND OF THE INVENTION In the conveyance of high-temperature media, the problem of shaft sealing in centrifugal pumps causes special difficulties. First, because there are only few work materials suitable for the sealing of shafts, that is, materials that can stand up under high temperature; and second, because the packings, respectively, shafts are subject to greater wear and tear due to higher temperatures. Many different steps have been taken to cool down thetemperatures of the pumps in the area of the shaft sealing to an acceptable figure. Most frequently used is that of casing cooling by means of a cooling liquid, where a cooling jacket is placed around the shaft sealing, while cooling fluid constantly flows through the cooling jacket. However, during the operation of the pump, there must always be sufficient cold fluid available and this fluid is sent either continuously through the cooling jacket (as, for instance, water), or it is cooled back down to a low temperature in a special cooling system, after running through the cooling jacket, before being used over again.

In other pump designs, the shaft sealing was placed away from the pump conveyance chamber and both of them were connected with each other only through a narrow shaft slit in order thus to achieve a sufficient temperature gradient from thepump toward the packing. The liquid which is between the pump and-the shaft sealing is cooled down to the desired value through heat transfer to the environment. When heat is given off to the environment only through radiation and natural convection of the surrounding air, then, if the temperature of the pumped medium is high, the interval between the shaft sealing and the pump must be very great, which leads to a major construction effort and very great structural length. Instead, additional cooling devices can be provided, such as by special fans, which generate a cooling air stream directed at the sealing housing, or a portion of the stream can be taken from the conveying current of the pump, to be conducted through a cooling device and then fed into a slide ring packing chamber for rinsing. But such additional cooling devices are also expensive.

' SUMMARY OF THE INVENTION ature having a shaft sealing housing arranged on the drive or imput side and which connected with the conveyor chamber of the pump only by means of a narrow shaft slit.

It is an object of this invention to provide a pump unit which will require a smaller expenditure for the additionalcooling devices.

The solution according to the invention consists in the fact that there is arranged an air-cooled drive motor in a manner such that the shaft sealing housing will lie in a cooling air stream coming out of the motor. In this manner there is obtained a sufficient reduction of the temperature in the area of the shaft packing without any additional fans which in the hitherto known models resulted in a considerable expenditure.

It. is understood that the use of air-cooled electric motors for the powering of pumps is known. However this invention is based on the discovery that the cooling air of the motor can also [still] be used for cooling the shaft sealing housing although it has already been heated up through absorption of heat from the motor.

Especially effective cooling can be achieved according to this invention with a heating shield arranged between the shaft sealing housing and the centrifugal pump, if the cooling air current is aimed at the heat shield and if the shield contains a guidance device, respectively, if it is made as a guidance device, which deflects the cooling air stream from the pump.

The heat shield, first of all, holds back the heat irradiated from the pump in the direction toward the sealing housing, and second, prevents the cooling air stream of the motor from additionally flowing also around the pump itself and producing undesired cooling. It can also be used for guiding the air streaming out as in the case of an externally cooled electric motor, at an interval from the shaft toward the shaft sealing housing which is to be cooled off. Particularly effective cooling of the shaft sealing is achieved according to the invention when the shaft sealing housing has cooling ribs.

Advantageously, the shaft packing housing is provided with lateral ribs and the guidance device guides the cooling air stream parallel to the lateral ribs toward the housing of the shaft packing.

In other cases, especially for internally cooled motors, it is desirable, alternatively, to provide the shaft packing housing with longitudinal ribs, whereby the guidance device deflects the cooling air stream after flowing around the shaft packing radially outward. The heat shield as such here serves the same purpose as in the unit with the laterally-ribbed shaft sealing housing.

It is very advantageous in a shaft packing housing provided with ribs for the height of the ribs to increase from the motor side to the pump side. This provides intensive cooling on that side of the shaft packing housing on which there is the higher temperatures.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. ,1, a side view of a pump unit with rib-less shaft sealing housing;

FIGS. 2 and 3, corresponding side views with a laterally-ribbed and longitudinally-ribbed shaft packing housing.

DESCRIPTION THE PREFERRED EMBODIMENTS According to FIG. 1, pump 1 is driven by an externally-cooled electric motor 2. The fan or blower lid 3 covers the motor fan which drive the cooling air inthe direction indicated by arrows. Pump shaft 4 is sealed toward the outside by a shaft packing [not shown] in the shaft sealing housing 5. Between the pump shaft 4 and the surrounding housing part, there is only a narrow shaft slit between the pump and the shaft sealing housmg.

The embodiment according to FIG. 2 differs from the one in FIG. 1 by shaft sealing housing 5 having laterally arranged cooling ribs 6 and that between pump 1 and shaft sealing housing 5 there is a heat shield 7 which is connected with flange 10 via a poor heat-conducting connecting body 8. Also, heat shield 7 in the lower area has guidance devices 9 which deflect the cooling air flowing in from the motor laterally to the original direction of flow and guide it parallel over the lateral ribs of the sealing housing. Heat shield 7 constitutes the barrier for the heat radiated from the pump toward the housing packing and the motor and prevents the cooling air of the electric motor which sweeps over the shaft sealing from also sweeping over the pump and producing an undesired cooling effect here. The heat shield 7 also causes the air, which in externally cooled electric motors flows off at a certain radial distance from the shaft, to touch the shaft sealing housing in sufficient quantity. The outside diameter of cooling rib 6 increases from the motor side to the pump side. The arrows designate the cooling air stream and it can be seen that the guidance of the cooling air can give an optimum cooling effect on the shaft sealing housing.

The arrangement according to FIG. 3 is similar to that of FIGS. 1 and 2, unless otherwise indicated and to the extent that this therefore does not clearly emerge from the drawings. In the case of motor 2 we are dealing with an internally cooled electric motor in which the cooling air flows inside the housing and, as indicated by the arrows, comes out of the housing nearer to the shaft than in externally cooled motors. It thus directly hits the shaft sealing housing 5 whose ribbing 6 is lined up longitudinally. In contrast to the example in FIG. 2, the cooling ribs 6 of the shaft sealing housing 5 are over-flowed by the motor cooling air inthe longitudinal direction, i.e., parallel to the shaft, and the motor cooling air is evacuated radially outward only after it has flowed over the cooling ribs through the heat shield 7 which is made in the form of radial deflection device-'9.

Obviously, the embodiments shown are exemplary only and a wide variety of embodiments may be devised without departing from the spirit and scope of the invention.

What is claimed is:

1. In a pump unit having drive motor means and a centrifugal pump for the conveyance of high temperature media, the improvement which comprises a shaft sealing housing connected with the conveyor chamber of said pump being on the driving side and cooledby an air stream, said housing communicating with said conveyor chamber only by a narrow slit about the shaft said motor means having means to air-cooled the drive motor means and mounted so that said shaft sealing housing lies in the air stream coming out of said motor means, and a heat shield between said shaft sealing housing and said centrifugal pump, said shield having guidance means deflecting the air stream back toward the housing of the shaft packing away from said centrifugal pumps.

2. The pump unit according to claim 1 including that cooling ribs on said shaft sealing housing.

3. The pump unit according to claim 2 wherein said shaft sealing housing is provided with lateral ribs and said guidance means deflects the air stream parallel to said lateral ribs toward the housing of the shaft packing.

4. The pump unit according to claim 2 wherein said shaft sealing housing is provided with longitudinal ribs and said guidance means deflects cooling air after flowing around the shaft sealing radially outward.

5. The pump unit according to claim 2 wherein the height of said ribs on said shaft sealing housing increases from the motor side to the pump side.

6. The pump unit according to Claim 1 wherein said centrifugal pump is a single stage pump. 

1. In a pump unit having drive motor means and a centrifugal pump for the conveyance of high temperature media, the improvement which comprises a shaft sealing housing connected with the conveyor chamber of said pump being on the driving side and cooled by an air stream, said housing communicating with said conveyor chamber only by a narrow slit about the shaft said motor means having means to air-cooled the drive motor means and mounted so that said shaft sealing housing lies in the air stream coming out of said motor means, and a heat shield between said shaft sealing housing and said centrifugal pump, said shield having guidance means deflecting the air stream back toward the housing of the shaft packing away from said centrifugal pumps.
 2. The pump unit according to claim 1 including that cooling ribs on said shaft sealing housing.
 3. The pump unit according to claim 2 wherein said shaft sealing housing is provided with lateral ribs and said guidance means deflects the air stream parallel to said lateral ribs toward the housing of the shaft packing.
 4. The pump unit according to claim 2 wherein said shaft sealing housing is provided with longitudinal ribs and said guidance means deflects cooling air after flowing around the shaft sealing radially outward.
 5. The pump unit according to claim 2 wherein the height of said ribs on said shaft sealing housing increases from the motor side to the pump side.
 6. The pump unit according to Claim 1 wherein said centrifugal pump is a single stage pump. 